Effects of particle morphology, pore size and surface coating of mesoporous silica on Naproxen dissolution rate enhancement

Naproxen (Nap) is a commonly used drug for antiphlogosis and analgesia, but its dissolution rate in water is quite low. In this work, the dissolution behavior of Nap after loading in mesoporous silica materials was investigated in a simulated intestinal fluid (pH = 6.8). The results indicated that the pore sizes, morphologies and surface chemical groups of the mesoporous silica were significant factors on the dissolution behavior of Nap. The physical state of encapsulated Nap was affected by the pore sizes of mesoporous silica, which influenced its dissolution rate. Amorphous Nap exhibited a higher dissolution rate than crystallized Nap, even though the larger pore size could facilitate its diffusion from the matrix. The effect of the morphology of mesoporous silicas on the dissolution of Nap can be ascribed to the length of pore channels, that the longer channel showed a longer diffusion pathway of Nap. Moreover, the release rate of Nap from functionalized mesoporous materials was effectively controlled compared with that of unmodified materials.